title: Lanthionine ketimine ethyl ester partially rescues neurodevelopmental defects in unc-33 (DPYSL2/CRMP2) mutants.
abstract: Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite with potent neurotrophic activity. Proteomics indicate that LK interacts with collapsin response mediator protein-2 (CRMP2/DPYSL2/UNC-33), a brain-enriched protein that was shown to regulate cytoskeletal remodeling, neuronal morphology, and synaptic function. To elucidate further the molecular interplay and biological action of LK and UNC-33, we began examining the nervous system of Caenorhabditis elegans nematodes in which both LK concentrations and UNC-33 protein were manipulated. To this end, a cell-permeable LK-ester (LKE) was administered to developing C. elegans engineered to express yellow fluorescent protein (YFP) in cholinergic neurons (strain RM3128) or green fluorescent protein (GFP) in GABAergic neurons (strain CZ1200), and neural morphology was assessed. Fluorescent imaging analyses show that LKE exposure to wild-type animals induced neural commissure outgrowth, crossing over, and bundling in both neurites from GABAergic and cholinergic motor neurons. Additionally, when unc-33(e204) hypomorph mutant nematodes (D389N substitution mutants) were exposed to LKE, both the neuroanatomical defects of incomplete dorsoventral neural commissures and the ventral nerve cord gaps were partially rescued. In contrast, LKE did not rescue ventral nerve cord gaps found in unc-33(mn407) null mutant. Together these data suggest possible functions for LK as a regulator of neuritic elongation, corroborate roles for UNC-33/CRMP2 in the mechanism of LKE activity, and suggest the potential of LKE as a therapeutic molecule for neurological diseases involving CRMP2 dysfunction.
authors.affiliation: Department of Biological Sciences, Southwestern Oklahoma State University, Weatherford, Oklahoma, USA.
authors.forename: Caleb
authors.initials: C
authors.lastname: Hubbard
authors.forename: Erica
authors.initials: E
authors.lastname: Benda
authors.forename: Tyler
authors.initials: T
authors.lastname: Hardin
authors.forename: Taylor
authors.initials: T
authors.lastname: Baxter
authors.forename: Elizabeth
authors.initials: E
authors.lastname: St John
authors.forename: Sean
authors.initials: S
authors.lastname: O'Brien
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hensley
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Holgado
mesh_terms: D000367:Age Factors; D000603:Amino Acids, Sulfur / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D001426:Bacterial Proteins / Q000235:genetics; D001927:Brain Diseases / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D002658:Developmental Disabilities / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D004195:Disease Models, Animal; D059330:GABAergic Neurons / Q000187:drug effects / Q000473:pathology; D008124:Locomotion / Q000187:drug effects / Q000235:genetics; D008136:Longevity / Q000187:drug effects / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009414:Nerve Growth Factors / Q000235:genetics*; D009420:Nervous System / Q000187:drug effects; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000603:Amino Acids, Sulfur; D001426:Bacterial Proteins; D029742:Caenorhabditis elegans Proteins; D008164:Luminescent Proteins; D009414:Nerve Growth Factors; D018696:Neuroprotective Agents; C078652:unc-33 protein, C elegans; C054562:yellow fluorescent protein, Bacteria; C035499:lanthionine ketimine
keywords: C. elegans; UNC-33; collapsin response mediator protein; lanthionine ketimine; synaptic connectivity